Researchers onboard were able to point their cameras out the windows of the aircraft and capture some of the scale and beauty of the frozen scene below.

The PIG drains a vast area of west Antarctica that is roughly equivalent to two-thirds the area of the UK. The glacier regularly calves large chunks from its floating front, or shelf, which pushes out into the Amundsen Sea.

This particular berg came away in October and was first noticed by satellites.

Image copyrightNASA-USGS LANDSAT/EARTH OBSERVATORYTImage caption
This latest berg broke away from the PIG in October

The production of bergs at the forward edge of an ice shelf is part of a very natural process.

It is how a glacier system like Pine Island maintains equilibrium: the ejection of bergs inevitably follows the accumulation of snowfall inland.

Image copyrightNASA ICEBRIDGE/Kate RamsayerImage caption
Sea-ice forms in a rift created when the B-46 broke off from the PIG

That said, the PIG has come under close scrutiny because it has shown evidence of thinning and acceleration.

Long-term satellite studies indicate that it has been dumping considerable volumes of ice into Amundsen Bay, pushing up global sea levels.

Image copyrightNASA ICEBRIDGEImage caption
The PIG drains an area of West Antarctica that is about two-thirds the size of the UK

The name of the new berg comes from a classification system run by the US National Ice Center, which divides the Antarctic into quadrants.

The B quadrant covers the Amundsen Sea sector, and this block is the 46th in the series. It - and any large daughter blocks - will need to be tracked because of the potential hazard posed to shipping.

B-46 is dwarfed by the mighty A-68 berg, which broke away from the Larsen C Ice Shelf in 2017. It covers an area approaching 6,000 sq km.